The present invention deals with catheters. More specifically, the present invention deals with delivery of a small bolus of liquid with a catheter.
A wide variety of different mechanisms and techniques have been developed in order to treat coronary disease. However, such techniques and devices are typically drawn to the physical manipulation of biological tissues, such as heart tissue, or other vascular tissue within the vascular system.
For example, some treatment techniques are drawn to the physical removal or dilation of restrictions (stenoses and total occlusions) in the vasculature. Techniques for dealing with this type of disease have included percutaneous transluminal coronary angioplasty (PTCA) in which an angioplasty balloon catheter is inserted into the body via the femoral artery and positioned across a restriction in an artery. The balloon is inflated to widen the restriction and restore blood flow to portions of the heart muscle previously deprived of oxygenated blood. Implantation of stents using PTCA is also a common technique for opening an arterial restriction.
Another technique for dealing with vascular disease includes coronary artery bypass graft (CABG) procedures. Such procedures typically include the placement of a graft at a desired location in the vasculature to supplement blood flow to the area previously deprived of blood (or provided with reduced blood flow) due to the vascular restriction. One common type of CABG procedure involves placement of a sapphenous vein graft (SVG) between the ascending aorta proximal of the restriction, and a region in the restricted vessel distal of the restriction.
Another technique for dealing with vascular disease includes an atherectomy procedure. In an atherectomy procedure, an atherectomy device is placed in the vasculature proximate the restriction. The atherectomy device is deployed to physically cut away, abrade, or otherwise physically remove, the occlusive material from the restricted vessel. The portions of the restriction which are severed by the atherectomy device are subsequently removed by aspiration, or by another suitable device.
Another technique called transluminal myocardial revascularization is also receiving attention in the medical community as an acceptable therapy.
Various drug therapies have also been developed. Such therapies have been used in place of, and in conjunction with, the above mentioned therapies under certain circumstances. For example, during grafting procedures, it may be desirable to deliver drugs to the graft site which inhibit the formation of thrombus. In addition, some drug therapies have been developed which involve the delivery of drugs directly to the heart tissue. With recent advancements in the pharmaceutical industry, other drug therapies have also become desirable. Some such recent pharmaceutical developments include the development of gene therapy drugs, such as growth factors.
A transluminal technique for delivering the drugs, along with the various types of known positioning and visualization techniques commonly used with transluminal treatments, can be highly desirable. The drug therapies typically require site specific administration of the drug. Transluminal techniques can be effectively used to deliver a liquid material to a selected site in the vasculature.
However, drug therapies, can be prohibitively expensive. For example, newly developed drugs are commonly extremely expensive and can only be administered in any pragmatic fashion in very low volumes. Typically, such drugs only need to be administered to the vascular site being treated. However, there is no technique available to date by which the site to be treated can be accessed transluminally with a catheter and which enables only a very small quantity of drug to be delivered from the distal portion of the catheter to the treatment site.
Rather, conventional transluminal drug delivery catheters require a proximal infusion device which is connected to a proximal end of the infusion catheter and which is used to pressurize a fluid or infusate which contains the drug to be delivered. The catheter is filled with the infusate and the drug is administered at the distal portion of the infusion catheter (upon pressurization of the infusate) after the catheter is inserted and properly positioned. While the internal volume of such infusion catheters is typically small, it is still much too large to make drug delivery with extremely expensive drugs practical.
The present invention is drawn to the delivery of a low volume bolus of drug or other treatment material to the myocardium, a vessel, or any other organ or area for which transluminal access is desirable. For example, anti-arrhythmia drugs may be injected into the myocardium using the present invention for electrophysiological therapy. Also, growth factors and other gene therapy substances can be injected into the myocardium for myocardial revascularization.
In one embodiment, the catheter system includes a catheter having a proximal end, a distal end, and a lumen extending therein. An elongate member slidably disposed in the lumen has a distal end located proximate the distal end of the catheter. An administering portion is disposed at the distal end of the catheter and is configured to express a bolus of liquid in response to positive pressure in a distal portion of the lumen created by movement of the elongate member distally in the lumen.
The present invention provides a drug delivery catheter having a minimal dead space so as to minimize the amount of residual drug left in the catheter after administering the drug. Preferably, the drug delivery catheter of the present invention provides a dead space of less that 0.32 cc, including the dead space in the proximal manifold and the remainder of the catheter. More preferably, the drug delivery catheter of the present invention provides a dead space less than 0.15 cc, and ideally less than 0.08 cc.
The present invention also includes a method of administering a liquid to a treatment site. A catheter, having a proximal end, a distal end and a ok lumen extending therein, as well as an elongate member, slidably disposed in the lumen, are provided. The distal end of the catheter is transluminally positioned proximate the treatment site. The catheter is charged by placing a bolus of the liquid in a distal end of the lumen between a distal end of the catheter and a distal end of the elongate member. The elongate member is then moved distally within the lumen to express the bolus from the distal end of the catheter.
Also, the present device should not be limited to implementation using only conventional catheters per se, but also contemplates any steerably, maneuverable syringe structure. Thus, the term catheter should be construed to include both conventional catheters and elongate, maneuverable syringe structures suitable for maneuvering, manipulation, tracking and steering within a vessel.
The catheter system can be navigated through several lumens and cavities within the body. Intravascular access by the femoral, brachial and radial arteries is contemplated for accessing target sites within the heart or peripheral vasculature. Alternatively, the catheter may be navigated into the ventricles of the heart by way of the aorta for direct treatment of the heart muscle (myocardium). Yet another alternative for accessing the heart chamber is via the vena cava. Lastly, nonvascular ducts or lumens within the body can be accessed for drug delivery such as for cancer treatment.
In accordance with another embodiment of the present invention, a collapsible drug reservoir is included in the catheter and is collapsed to administer the bolus of liquid.